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Bruno Zumino, Inventor of Supersymmetry, Dies at 91

Physics Mourns the Loss of Beloved Professor

Tuesday, June 24, 2014

Bruno Zumino, a professor emeritus of physics at the University of California, Berkeley, who was best known for developing supersymmetry, a theory now considered as a leading candidate for explaining the fundamental forces of nature, died late Saturday, June 21*, at his home in Berkeley, Calif. He was 91.

Bruno Zumino is one of the originators of the theory of supersymmetry, used to describe the particles and forces in nature.

Supersymmetry or SUSY, developed in the early 1970s at the European Center for Nuclear Research (CERN) in Geneva, Switzerland, by Zumino and Julius Wess, was conceived to explain particle interactions involving three of the four main forces in nature – the strong, electromagnetic and weak forces. One consequence of the theory is that every particle we see today has a supersymmetric partner – the quark has an associated squark, for example, while the electron has a selectron.

Zumino and Stanley Deser, and separately Dan Freedman, Sergio Ferrara and Peter Van Nieuwenhuizen, later extended the so-called “Wess-Zumino model” of supersymmetry to include gravity, creating a theory called supergravity.

To date, none of these superpartners has been detected, though CERN’s Large Hadron Collider, which in 2012 produced evidence for the Higgs boson, a particle that endows the rest of matter with mass, is now looking for heavier particles that would be evidence of supersymmetry. Scientists even hold out hope that one of the superpartners will be the elusive dark matter particle that, despite making up one-quarter of the energy in the universe, so far has gone undetected.